1. Field of the Invention
The present invention relates to a process for producing a nitrile compound and a catalyst to be used therefor. More particularly, the present invention is concerned with a process for producing a nitrile compound from a corresponding alkyl group-substituted aromatic compound or alkyl group-substituted heterocyclic compound and a mixed gas containing ammonia and oxygen; and with a catalyst to be used therefor.
2. Description of the Related Arts
A nitrile compound which is derived from an alkyl group-substituted aromatic compound is an important intermediate in organic chemical industries. Phthalonitrile as an example of said nitrile compound is used as a starting raw material for xylylenediamine which is useful as a curing agent for synthetic resins, agricultural chemicals, diisocyanate and epoxy resins. On the other hand, cyanopyridine which is derived from an alkyl group-substituted heterocyclic compound is used as a starting raw material for nicotinic acid amides and nicotinic acid that are useful substances in the industrial fields including pharmaceuticals, feed additives and food additives.
There have been proposed various processes for producing aromatic nitrites by subjecting an alkyl group-substituted aromatic compound to ammoxidation by the use of ammonia and oxygen. For example, Japanese Patent Publication No. 19284/1970 (Sho-45) describes a ternary catalyst consisting of vanadium, chromium and boron. Japanese Patent Publication No. 45860/1974 (Sho-49) describes a ternary catalyst which consists of vanadium, chromium and boron in the form of vanadium oxide, chromium oxide and boron oxide, respectively, in an atomic ratio of 1:(0.5 to 2.0):(0.1 to 1.2), and which is supported on silica as the carrier in an amount of 30 to 60% by weight based on said carrier. Japanese Patent Publication No. 15028/1976 (Sho-51) corresponding to U.S. Pat. No. 4,082,786 describes a quaternary catalyst which consists of a vanadium oxide, a chromium oxide, boron oxide and a phosphorus oxide in an atomic ratio of 1:(0.5 to 2.0):(0.1 to 1.2):(0.01 to 0.3). Further, Japanese Patent Application Laid-Open No. 275551/1989 (Hei-1) corresponding to U.S. Pat. No. 4,985,581 describes a quaternary catalyst consisting of a vanadium oxide, a chromium oxide, a molybdenum oxide and boron oxide in an atomic ratio of 1:(0.5 to 2.0):(0.01 to 1.2):(0.01 to 1.2).
On the other hand, as an example of process for producing a nitrile compound by subjecting a corresponding alkyl group-substituted heterocyclic compound to ammoxidation, Japanese Patent Application Laid-Open No. 275564/1989 (Hei-1) corresponding to U.S. Pat. No. 4,963,087 describes a process for producing cyanopyridine by reacting methylpyridine with ammonia and an oxygen-containing gas in the presence of a catalyst which consists of a vanadium oxide, a chromium oxide and boron oxide, and which is supported on silica as a carrier.
A large amount of reaction heat is generated in the case of ammoxidation reaction in which an alkyl group-substituted compound is reacted with ammonia and oxygen in a gas phase, thereby making it extremely difficult to properly control the reaction temperature. In order to overcome such an difficulty, a reactor of fluidized bed type is particularly effective. On the other hand, Japanese Patent Publication No. 15028/1976 (Sho-51) corresponding to U.S. Pat. No. 4,082,786 and Japanese Patent Application Laid-Open No. 275551/1989 (Hei-1) corresponding to U.S. Pat. No. 4,985,581 describe the improvement in the yield of a nitrile compound produced by ammoxidation by the use of a catalyst for a reactor of fluidized bed type. Likewise, Japanese Patent Publication No. 19284/1970 (Sho-45) and Japanese Patent Publication No. 45860/1974 (Sho-49) describe the improvement in the yield of a nitrile compound produced by ammoxidation through the addition of a phosphorus oxide and a molybdenum oxide to a vanadium oxide, a chromium oxide and boron oxide. Nevertheless, the yield of the nitrile compound is not necessarily sufficed by any of the above-mentioned prior arts.